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Biomedical subjects

U Krause

Publications and source records attributed to U Krause.

At least 19 recordsLinked to original sources
PubMed1992

Effects of insulin-like growth factor I on the rates of glucose transport and utilization in rat skeletal muscle in vitro.

1. The effects of insulin-like growth factor I (IGF-I) on the rates of glucose transport and utilization and its interaction with insulin were investigated in rat soleus muscle in vitro. IGF-I increased the rates of glucose transport, lactate formation, glycogen synthesis and the flux of glucose to hexose monophosphate, but it had no effect on the rate of glucose oxidation or glycogenolysis. 2. In the absence of insulin, low levels of IGF-I (0-30 ng/ml) increased the rate of glycolysis and the content of fructose 2,6-bisphosphate, but the content of glucose 6-phosphate remained unaltered; at higher levels of IGF-I (300-3000 ng/ml) the rate of glycolysis and the content of fructose 2,6-bisphosphate showed a further modest increase, but the content of glucose 6-phosphate doubled. Similar changes were seen when the level of insulin was increased from basal (0-0.4 ng/ml) to maximal (40 ng/ml). 3. Neither IGF-I nor insulin affected the contents of ATP, ADP, AMP, phosphocreatine or citrate. 4. Maximal concentrations of IGF-I increased the rate of lactate formation to a greater extent than did maximal concentrations of insulin. 5. In the presence of IGF-I, the rate of glucose utilization was less responsive to insulin. 6. The results suggest that, in rat skeletal muscle: (a) IGF-I increases the rates of glucose transport and utilization independently of insulin, and has a preferential effect on the rate of lactate formation; (b) the effects of IGF-I and insulin are not additive; (c) in addition to its effects on glucose transport, IGF-I increases the rate of glycogen synthesis and may stimulate glycolysis at the level of 6-phosphofructokinase; (d) changes in the content of fructose 2,6-bisphosphate may be part of the mechanism to regulate glycolytic flux in skeletal muscle in response to either IGF-I or insulin.

Animals↗
PubMed1992

Time-related effects of thyrotropin-releasing hormone (TRH) on the pituitary-thyroid axis and extrathyroidal targets.

Thyrotropin-releasing hormone (TRH) is a tripeptide and acts as a stimulator of the pituitary-thyroid axis as well as having a great number of well defined extrathyroidal functions. Studies in experimental animals have shown, that TRH also has a role as a neuromodulator within the autonomous nervous system. In this study we analyzed the effects following peripheral administration of TRH (200 micrograms, 400 micrograms) in patients with endocrinological disorders and in healthy females and males. By means of a questionnaire, patients were asked about possible (side-) effects; ventilatory and cardiovascular monitoring was performed during steady state. The pulsatile TSH-secretion pattern was analyzed and thyroid and stress hormones were measured in the blood prior to and following TRH i.v. Frequent symptoms afer TRH were feeling of heat (58%), stimulation of respiration (61%), palpitations (39%), micturition urge (52%) and restlessness (32%). Apparative monitoring demonstrated a short stimulation of respiration and an increase of heart rate. After 400 micrograms TRH i.v., blood levels of ACTH decreased slightly (p less than 0.01) but levels of T3, T4, epinephrine, norepinephrine and cortisol remained unchanged (p greater than 0.05). TSH-levels were low during daytime and showed a surge at night.

Adult↗
PubMed1992

The influence of testosterone substitution on bone mineral density in patients with Klinefelter's syndrome.

The aim of this study was to clarify the extent of bone mineral deficiency in patients with Klinefelter's syndrome on the premise that testosterone substitution could prevent this deficiency. Bone mineral density was measured by single-photon absorptiometry in 42 patients with Klinefelter's syndrome, (21 patients without therapy, 10 with testosterone substitution before the age of 20 and 11 patients with testosterone substitution beginning after the age of 20). We found significantly lower bone mineral density in patients without therapy and in patients when the therapy began later compared to normal individuals. Patients with early therapy showed a high proportion of normal values of bone mineral density. We found a positive correlation between bone mineral density and plasma testosterone and a negative correlation between plasma testosterone and age for patients without therapy. These findings suggest that low testosterone levels before or during puberty cause inadequate bone development and low bone mineral density in Klinefelter's syndrome. Only early testosterone substitution may prevent bone mineral deficiency. Later substitution no longer affects bone mineral density.

Adult↗
PubMed1992

[Effect of the manganese content in laying hen feed with different Ca and mineral levels on the egg shell quality and bone mineralization of hens].

Four experiments with 270, 44, 432 and 66800 Leghorn hens were carried out to investigate the influence of various Mn additions to diets differed in mineral or Ca contents on egg shell quality. The addition of 300 mg Mn/kg diet improved significantly egg shell breaking strength by 4 N over one year. The supply of 50-500 mg Mn/kg diet for 10-24 weeks of the second half of laying year did not influence the egg shell quality. Addition of mineral mixture or Ca grit to layer rations with adequate or higher Mn levels did not influence egg shell strength. High mineral content in a low manganese diet increased number of cracks by 3%. Strength, weight and ash content of tibia were significantly reduced by feeding a low mineral level. Addition of 50-150 mg Mn per kg low mineral diet normalized partially tibia stability in young hens. It was concluded that supplied dietary Manganese influences calcification positively only in young hens. High levels of Ca did not influence the effects of Mn. 50 mg Mn per kg layers mixture have been considered as an essential supply.

Animal Feed↗
PubMed1992

Pavlovian conditioning of corticotropin-releasing factor-induced increase of blood pressure and corticosterone secretion in the rat.

Corticotropin-releasing factor (CRF) is clearly involved in the central regulation of the pituitary-adrenal axis and, moreover, of autonomic nervous system functions. Enhanced sympathetic activity with subsequent increases in blood pressure and heart rate and attenuation of the baroreceptor reflex results from the intracerebroventricular (i.c.v.) administration of CRF. Additionally, the peptide has a variety of potent effects on behavioural responses in animals similar to those observed after an experimentally evoked stress. It was therefore of obvious interest to examine whether CRF is a possible mediator of the learning processes associated with physiological stress reaction patterns. This report clearly demonstrates a classical conditioning of the endocrine (i.e. corticosterone secretion) and haemodynamic (i.e. blood pressure) sequelae following central CRF application and thus indicates that this mechanism is of physiological significance for learned stress responses.

Animals↗
PubMed1992

Postprandial pattern of triglyceride-rich lipoprotein in normal-weight humans after an oral lipid load: exaggerated triglycerides and altered insulin response in some subjects.

In 13 healthy, male nonsmokers (mean age: 25.7 +/- 2.4 years) with normal fasting triglycerides we investigated postprandial changes of triglycerides in several lipoprotein fractions. After a 12-hour overnight fast they ingested a standardized lipid load (1,017 kcal) including 30,000 IU retinyl palmitate. Postprandially, total triglycerides increased significantly (p < 0.001) to a peak value of 221 +/- 81 mg/dl at 5 h. Two subjects had an exceptionally strong triglyceride response (peak values: 363 and 390 mg/dl). They had the highest levels of retinyl palmitate in the chylomicron and the nonchylomicron fraction, and one of them showed elevated intermediate-density lipoprotein values throughout the test period. In addition, they showed an altered early and an increased late postprandial insulin response. Thus, our data provide evidence that an exaggerated postprandial triglyceride response may point to an increased atherogenic risk even in healthy subjects with normal fasting triglycerides.

Adult↗
PubMed1992

Effects of corticotropin-releasing hormone on the postoperative course of elderly patients under long-term artificial respiration.

In both human and animal studies a stimulatory effect of corticotropin-releasing hormone (CRH) on respiration and on cognitive parameters has been demonstrated. Our own studies employing human CRH (hCRH) iv in healthy volunteers and different groups of patients have shown hCRH to be a safe drug. We prospectively studied the clinical effects of a standardized dose of 100 micrograms hCRH iv in 12 elderly patients following major abdominal surgery who remained comatose and were under prolonged respirator therapy over a mean period of 37 days. Cardio-respiratory parameters, blood gas values, plasma cortisol and catecholamines were evaluated before and 30 min following hCRH injection. Furthermore, vigilance was tested using a score system. Ventilation was markedly enhanced following hCRH injection while the cardiovascular parameters were only moderately affected. Vigilance was augmented in all subjects and improved impressively in five patients. The changes were of great benefit for the patients treated and supported their respirator weaning procedures and mobilization training.

Abdomen↗
PubMed1992

Effects of in-vivo administration of insulin-like growth factor-I on the rate of glucose utilization in the soleus muscle of the rat.

This study investigated the effects of insulin-like growth factor-I (IGF-I) administered to rats in vivo on the soleus muscle isolated from these rats. In order to study the interactions between IGF-I and insulin, the soleus muscles were incubated in the presence of various concentrations of insulin. IGF-I (190-200 micrograms) was given twice daily; the rats were killed 1 h after one injection of IGF-I (acute administration) or after treatment with IGF-I for 10 days (prolonged administration). The level of IGF-I in plasma was increased by approximately 100% after acute administration and by around 30% after 10 days of treatment with IGF-I. Acute administration of IGF-I to the rats increased the flux of glucose to hexose monophosphate and the rates of lactate formation and glycogen synthesis in the soleus muscles; however, the responsiveness of these muscles to insulin was lost: the increase in the rate of glucose utilization by IGF-I at physiological concentrations of insulin (10 or 100 mU/l) was similar to that observed at maximal concentrations of insulin (1000 mU/l). Similar results were obtained after prolonged treatment of the rats with IGF-I; however, the increase in the rate of glucose utilization was less pronounced than when IGF-I was given acutely and the muscles were still capable of responding to insulin.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

[Experiences with a modified implantation technique of Port-A-Cath systems as continuous venous access in infants and children].

Since April 1987 we implanted the Port-A-Cath infusion system in 60 children in the age of 2 months to 16 years (median: 4.3 years). We only used the adult system (Pharmacia). By one right side infraclavicular incision the silicon catheter was implanted into the jugular vein and also the port was fixed on the pectoral fascia. We saw one severe complication as a port perforation through the skin. 1.6% was the very low rate of complications which appeared in the median of the port using time of 168.5 days.

Adolescent↗
PubMed1991

Safety and side effects of human and ovine corticotropin-releasing hormone administration in man.

Synthetic human and ovine corticotropin-releasing hormone (hCRH, oCRH) are commonly used as a diagnostic tool of the hypothalamo-pituitary-adrenal axis. In this paper reports about side effects after various modes of CRH-application are analyzed and compared to our corresponding data of human studies with hCRH and oCRH. Generally, CRH is well tolerated after single administration and interval-application of standard doses, although minor side effects appear sometimes after higher doses (greater than 200 micrograms hCRH, oCRH) of CRH-bolus-injections. Predominantly the cardiovascular system (e.g. tachycardia, hypotension, flushing) is affected; neuropsychological symptoms are only seen sporadically (e.g. dizziness). Long term continuous infusion (several hours) of low CRH-doses (hCRH, oCRH) are well tolerated but side effects appear (see above) when cumulated doses of 200 micrograms-300 micrograms/h are given. Standard doses of hCRH and oCRH are also well tolerated in severely ill patients; it has to be considered that higher doses may provoke marked side effects in persons with neurologic disorders, in subjects with coronary heart disease and in patients with endocrinological disorders of the pituitary-adrenal axis, especially in those subjects in whom the blood-brain-barrier may have been damaged (e.g. head injury, intracranial operation). Single hCRH- and oCRH-bolus-injections in standard doses have a very low rate of complications, "non-standard" doses should provisionally be used only in clinical studies with well designed safety-precautions.

Animals↗
PubMed1991

[Frequency of thyroid gland carcinoma in hyperthyroidism].

From 1980 to 1989, 226 patients (199 females, 27 males, median age 41 [18-76] years) underwent surgery because of clinical hyperthyroidism. 152 patients had autoimmune thyrotoxicosis, and 74 functional autonomy. Histological examination of resected thyroid tissue revealed carcinoma in 6 cases (2.6%): 3 (2%) in autoimmune hyperthyroidism, and 3 (4%) in functional autonomy. Five tumours fulfilled the criteria for occult papillary thyroid carcinoma (highly differentiated, less than 1.5 cm diameter). One woman had both a multilocular papillary carcinoma and a medullary carcinoma without proven metastases. In none of the cases was a malignant tumour suspected preoperatively from sonography or scintigraphy studies. In the patients with occult carcinomas, extended bilateral subtotal resection was regarded as curative. In the patient with papillary and medullary carcinoma, remaining thyroid therapy was given. One patient with Basedow's (Graves') disease and a papillary carcinoma of diameter 1.3 cm received radioiodine at her own request. She and the four remaining patients received suppression therapy (150-200 micrograms L-thyroxine daily), with frequent follow-up. During follow-up for a mean period of 24 months (range 6-51 months) there were no metastases or tumour recurrences.

Adult↗
PubMed1991

Studies on facial temperature rise and involvement of serotonin in the respiratory stimulation by CRH.

Following an intravenous injection of 100 micrograms hCRH a facial flushing can frequently be observed along with respiratory stimulation. Both effects can be mediated by a common transmitter. Serotonin is well known to produce facial flush as well as to modulate respiration. In order to clarify is serotonin is a common mediator for facial flush and respiratory stimulation after i.v. application of hCRH, we studied the time course of facial skin temperatures and respiratory stimulation after intravenous injection of 100 micrograms hCRH in 10 healthy subjects. Furthermore, we measured respiratory stimulation after i.v. administration of 100 micrograms hCRH in 10 healthy subjects pretreated with the serotonin antagonist cyproheptadine. Facial skin temperatures reached maximum levels 9 min after CRH administration and remained raised for more than 60 min. Respiratory stimulation occurred within the first minute after CRH administration and reached a maximum during the second minute, but could no longer be observed after 10 min. Serum serotonin levels did not change after CRH stimulation in doses up to 3 micrograms/kg body weight), and cyproheptadine did not abolish the respiratory stimulation effect of hCRH in a dosage sufficient to suppress CRH.-induced cortisol secretion.

Adult↗
PubMed1991

Thyrotropin-releasing hormone has stimulatory effects on ventilation in humans.

Thyrotropin-releasing hormone (TRH) stimulates pituitary thyrotropin synthesis and release and also regulates autonomic nervous system functions by acting as a neuromodulator and neurotransmitter. In experimental animals a stimulation of ventilation by thyrotropin-releasing hormone was shown when applied at central nervous system sites that affect respiratory motor output. It was the goal of our study to investigate the respiratory properties of thyrotropin-releasing hormone on basal and stimulated (i.e. CO2-rebreathing) conditions following systemic thyrotropin-releasing hormone application in healthy humans. Thyrotropin-releasing hormone (200 micrograms, 400 micrograms intravenous) initiated a rapid short lasting rise of minute volume, ventilatory air-flow and alveolar oxygen tension under steady state breathing (P less than 0.001). Breathing frequency was less affected, heart rate rose concomitantly (P less than 0.001). While breathing with increasing concentrations of carbon dioxide, minute volume was higher under thyrotropin-releasing hormone than under placebo alone. Further effects (e.g. nausea, dizziness, palpitations) mostly appeared later than respiratory changes and thus may not be responsible for their initiation. Our findings prove systemic thyrotropin-releasing hormone to be a strong respiratory stimulant in man. Response in respiratory output was also accompanied by central nervous system-effects (e.g. dizziness, restlessness, augmented vigilance). The mode of thyrotropin-releasing hormone effects on respiration after peripheral administration is still speculative. An augmented sympathetic output or a direct receptor mediated action at central nervous system sites may be responsible, while a peripheral effect cannot be excluded.

Adolescent↗
PubMed1991

Unaltered pulsatile and circadian TSH release in euthyroid patients with endemic goitre.

To evaluate the pathophysiological role of TSH in goitrogenesis we investigated pulsatile TSH secretion in 11 patients with a non-toxic goitre and in 11 healthy controls. Thyroid volume was 40 +/- 10 ml in the goitre group and 15 +/- 4 ml in the controls as measured by ultrasound. Blood was sampled continuously via an indwelling venous catheter at 10-min intervals over 24 h. Neither the mean 24-h serum TSH levels (goitre 1.1 +/- 0.5 vs controls 0.9 +/- 0.4 mU/l) nor the nocturnal surge of TSH were significantly different between the two groups. The average of the TSH pulse frequency (goitre 10.8 +/- 3.7 vs controls 9.6 +/- 3.5 pulses/24-h) and of the TSH pulse amplitude (goitre 0.4 +/- 0.2 vs controls 0.3 +/- 0.1 mU TSH/l) as analysed by DESADE programme (detection of secretory activity by discrete deconvolution) did not differ in the two groups. Furthermore, there was no correlation between the volume of the thyroid gland and the dynamics of the TSH secretion. We conclude that our data do not suggest a relevant pathophysiological role of TSH secretion in the development of non-toxic goitre in man.

Adult↗
PubMed1991

Trace element intake (zinc, manganese, copper, molybdenum, iodine and nickel) of humans in Thuringia and Brandenburg of the Fed. Rep. of Germany.

The daily dry matter intake of 56 test persons between 20 and 60 years of age from four geographic groups (Wusterhausen and Vetschau in Brandenburg; Jena and Bad Langensalza in Thuringia) was registered on 7 consecutive days by means of the duplicate method. The Zn, Mn, Cu, Mo, I and Ni content of food and beverage dry matter and the daily intake of these trace elements were determined. During the test period, the ration contained 24-29 mg zinc, 6.8-9.2 mg manganese, 1.9-2.6 mg copper, 0.17-0.22 mg molybdenum, 0.10-0.18 mg iodine and 0.36-0.68 mg nickel per kg dry matter. The adults consumed 6.7-11.0 mg zinc, 2.0-3.8 mg manganese, 0.54-0.92 mg copper, 47-89 micrograms molybdenum, 30-67 micrograms iodine and 111-256 micrograms nickel per day. The living area had an effect on the Mn, I and Ni intake. The higher dry matter intake resulted in a better trace element supply of male test persons. The copper, molybdenum and iodine requirement recommended by the WHO was not met.

Adult↗
PubMed1991

[Studies on the influence of releasing hormones TRH and CRH on respiratory regulation].

Patterns of neuroanatomical distribution of Thyrotropin-releasing hormone (TRH) and Corticotropin-releasing hormone (CRH) and of their receptors in brain areas of humans and of animals suppose a regulating function of both peptides on regulation of respiration. In experimental animals TRH induces rhythmical and synchronous firing of defined neurons of nucleus tractus solitarii. In fetal sheep, endogenous and exogenous CRH promotes maturation of breathing rhythm genesis. In own human studies we demonstrated a modulation of respiration in healthy test-subjects - predominantly a stimulation of respiration - by systemic TRH and CRH. This effect persists also during hypercapnia, as we showed in patients and in 12 healthy test subjects while re-breathing CO2: when compared to placebo, CRH i.v. (200 micrograms. Bissendorf, Hannover, FRG) induces a significant (p less than 0.0001) shift of the ventilatory response curve to the left (petCO2 vs minute volume). Stimulation of respiration by CRH is independent of activation of the pituitary-adrenal axis. At present two analogues of CRH are available for application in humans (as a diagnostic of endocrinological disorders): human CRH and ovine CRH. Both analogues are comparably effective in stimulation of ventilation although sequence of effects is different in both analogues. We also evaluated the effect of CRH in 10 aged patients who were under prolonged respirator therapy after major abdominal surgery; both human and ovine CRH (100-200 micrograms i.v.) induced a profound and long lasting stimulation of ventilation under assisted respirator therapy. Vigilance was also markedly increased in all patients and thus was of therapeutic value. CRH also has a potential to alter sleep architecture in healthy and in diseased persons.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

[Coincidence of non-medullary thyroid cancer and hyperparathyroidism].

Hyperparathyroidism (HPT) and non-medullary thyroid carcinoma are not related by a common embryologic origin. In a 5-years period (1985-1989) 163 patients were operated for HPT at our hospital. Of these, 54 patients had concurrent thyroid disease, which was operated simultaneously. In 6 cases, thyroid carcinoma was found, e.g. 3.7% of all patients. This prevalence compares well to reports of different authors in the literature. The most probable explanation is the early diagnosis of asymptomatic occult papillary carcinomas; this was true in 4 of our 6 patients with thyroid malignancy.

Adenoma↗